I have a Pi3 connected via Ethernet to my router. I have configured router (not the Pi) to associate static IP addresses to the MAC addresses of eth0 and wlan0. When I boot up the Pi and run ifconfig, I can see that eth0 was assigned the correct IP, however wlan0 is up but does not have an IP assigned. Why is this? Btw, there is nothing in particular I am trying to achieve. Just playing around with the hardware.
I have played around with /etc/network/interfaces what I describe above happens under the setting
auto lo iface lo inet loopback auto eth0 iface eth0 inet dhcp auto wlan0 iface wlan0 inet dhcp
I have not configured wpa_supplicant. What I am trying to understand is how one could assign an IP to the wlan0 interface without connecting the pi via said interface. My naive understanding is that since the Pi is connected via Ethernet, and the WiFi interface is on the same piece of hardware it should be "discovered" and an DHCP running on router should assign IP, but obviously that's not how it works. So what am I missing?